Rotary perfecting machine for letterpress work



Dec. 23, 1958 G. KALDSCHMIDT 2,865,288

RGTARYPERFECTING MACHINE FOR LETTERPRESS WORK Filed July 13. 1954 2 Sheets-Sheet 1 INVENTOR G's-02c; A aDsw/Mwr ATTORNEY Dec. 23, 1958 G. KALDSCHMIDT 5 5 ROTARY PERFECTING MACHINE FOR LETTERPRESS WORK Filed July 13. 1954 2 Sheets-Sheet 2 INVENTOKR 6":096- K44 DSCHMIJJ 7' ATTORNEY United States Patent Q ROTARY PERFECTING MACHINE FUR LETTERPRESS WORK Georg Kaldschmidt, Dresden-Weisser Hirsch, G ermany,

assignor to Veh Druchmaschinenwerk Victoria, Herdenau, Germany Application July 13, 1954, Serial No. 443,093

Claims. (Cl. 101-229) This invention relates to a process of producing sheets printed on both sides in one passage in letterpress work and to a rotary perfecting machine for carrying out this process.

The disadvantages of letterpress printing compared with offset and intaglio processes are known. In order to render letterpress printing more efficient rotary sheet printing machines doing better work at lower cost and greater speed than the older presses have been developed. They deliver one sheet printed on one side at each revolution of the impression cylinder and, compared with modern high-speed Z-revolution machines, double the output at equal printing speed. Perfecting machines increase this output again 100 percent, since the sheets are printed on both sides on leaving the press.

Besides increasing output, sheet printing rotaries can meet also very exacting requirements as to quality of work, because, contrary to fiat bed presses, contact be tween the plate and impression cylinders practically occurs on a straight line.

The known perfecting machines of different designs are, however, open to the objection that they use fiat bed printing and are equipped with either a rocking impression cylinder or, as a rule, two impression cylinders. In the latter construction a sheet freshly printed on one side is immediately transferred to the perfecting cylinder with the result that the packing of the cylinder is soiled by ink offsetting from the printed side of the sheet and at intervals has to be manually or mechanically cleaned with oil, etc. while the machine is stopped. It is evident that this process is unsuited for producing high-grade work.

It is one of the objects of the invention to provide a rotary perfecting machine by which perfecting is performed after the first printed side of a sheet has been dried.

According to the invention, the plate cylinder serving for first form printing is arranged at such a distance from the perfecting plate cylinder that the sheet having received the first impression arrives at the perfecting cylinder only after the impression has dried. The transporting devices bridging the space between the cylinder printing the first form and the perfecting cylinder alternately consist of drums or cylinders provided with a smooth sheet metal jacket and drums provided with sheet metal segments axially displaceable on a shaft; each drum or cylinder being so disposed that the sheet having received the first impression cannot come into contact with them.

The adjacent transporting devices positively guide the sheets on their way from the first form cylinder to the perfecting cylinder, in a manner to prevent displacement of sheets. For this purpose both the transporting devices and the cylinders are fitted with grippers.

Blast nozzles using oxygen or dry air and being arranged above or below the transporting devices are provided to assist in drying. Infra-red drying may also be applied.

The invention further affords the advantage of ready "ice access within the frame of the machine, of a carriage for bringing the printing cylinders into and out of position for mounting in the machine.

To increase the productiveness of the new machine still more at least two plate cylinders are provided for each printing unit. While the machine is printing one job the free plate cylinder is made ready for the next one. For this reason provision is made for rapidly exchanging both the plate cylinder for first form printing and the one for perfecting. Easy supervision and accessibility of the two impression cylinders are insured also.

One embodiment of the invention is illustrated in the accompanying drawings, wherein Figure 1 is a diagrammatic side view of the machine;

Fig. 2, a side view of the sheet transporting'means;

Fig. 3, a side view of the gripper arrangement before transmitting a printed sheet;

Fig. 4 shows the gripper arrangement after transmitting a printed sheet;

Fig. 5 shows in diagrammatic view the path taken by the paper sheets through the machine during the. perfecting process;

Fig. 6 is a view of a sheet metal. jacket drum used in Q the transportaticnof the sheets; and

Fig. 7 is a view of the transporting drum showing the actually displaceable sheet metal segments, used in the transportation of the sheets.

By the feeding means. 1 a sheet to be printed is brought to finely adjustable guides for registration and then taken over by precision swing means 2 which transfers it, in conformity with the speed of the impression cylinder, to individual springy grippers 3 of the first form cylinder 4.

With the aid of the plate cylinder 5 the sheet is now printed on one side. The; grippers of the first form cylinder release the largest printed. sheet only after it has been fully printed out.

6 comprising a shaft 7 on which axially displaceable sheet metal segments 8 are so arranged that the freshly printed surface of a sheet cannot come in contact with them and is thus prevented from being slurred.

From the transporting device 6 the sheet printed on one side passes to the drum 9 formed of a sheet metal jacket and serving merely for further transportation of the sheet resting on it with its unprinted side.

From the drum 9 the grippers 3 thereof convey the sheet with its printed side inward to the drum 10 con structed like the transporting device 6. From drum 1d the sheet with its impression outside is moved by the grippers to the drum 11 which is of the same type as drum 9. On the way of the sheet printed on one side tube blasts 12 are provided for accelerating drying from without. The sheet with its printed side inward is conveyed from the drum 11 to the grippers of the perfecting cylinder 13 and receives an impression on its other side by means of the plate cylinder 14. After the largest printed sheet has been printed out it is taken over by the chain type deliverer 15 and passed to the stack with its perfected side up.

The transfer of a sheet having received its first impression from the cylinder 4 by means of the transporting device 6 and the drums and transporting devices 9, 1t), 11 to the perfecting cylinder 13 is positively effected by the grippers 3 to maintain perfect register.

The make-ready carriages 17 serve for moving plate cylinders that have been or are to be made ready to and from the machine.

I claim:

1. In a rotary perfecting machine for letterpress work, a mam frame, a perfecting unit, a printing unit mounted within said main frame comprising a plate cylinder and an impression cylinder for printing a sheet on one side,

From the cylinder 4 the sheet. with its printed side inward passes to the trans-porting device.

a first drum positioned in cooperative engagement with said impression cylinder, grippers on said first drum adapted to release the sheet after completion of printing thereon by said plate cylinder, axially parallel drum transporting and drying-promoting devices mounted on said main frame in a successive cooperating series for transferring a printed sheet to said perfecting unit from said first drum, said first drum and said drum transporting devices being mounted in position to prevent contact with the freshly printed side of the sheet to be transferred, alternate drums of said series being fitted with a sheet metal jacket and means for delivering a perfected sheet to a stack.

2. The rotary perfecting machine of claim 1 in which said drums are of equal diameter.

3. In a rotary perfecting machine for letterpress Work, a main frame, a perfecting unit, a printing unit mounted within said main frame comprising a plate cylinder and an impression cylinder for printing a sheet on one side, a first drum positioned in cooperative engagement With said impression cylinder, grippers on said first drum adapted to release the sheet after completion of printing thereon by said plate cylinder, axially parallel drum transporting and drying-promoting devices mounted on said main frame in a succesive cooperating series for transferring a printed sheet to said perfecting unit from said first drum, said first drum and said drum transporting devices being mounted in position to prevent contact with the freshly printed side of the sheet to be transferred, alternate drums of said series being fitted with a sheet metal jacket and means for delivering a perfected sheet to a stack, said first drum and an alternate drum being provided with axially displaceable sheet metal segments mounted on a shaft therein, said sheet metal segments being adapted to be displaced on said shaft to prevent contact with the printed side of a sheet to be transported.

4. In a rotary perfecting machine for letterpress Work, a main frame, a perfecting unit, a printing unit mounted within said main frame comprising a plate cylinder and an impression cylinder for printing a sheet on one side, a first drum positioned in cooperative engagement with said impression cylinder, grippers on said first drum adapted to release the sheet after completion of printing thereon by said plate cylinder, axially parallel drum transporting and drying-promoting devices mounted on said main frame in a successive cooperating series for transferring a printed sheet to said perfecting unit from said first drum, said first drum and said drum transporting devices being mounted in position to prevent contact with the freshly printed side of the sheet to be transferred, alternate drums of said series being fitted with a sheet metal jacket and means for delivering a perfected sheet to a stack, said drums being provided Withgrippers to positively guide the sheet to be transported.

5. In a rotary perfecting machine for letterpress Work, a main frame, a perfecting unit, a printing unit mounted within said main frame comprising a plate cylinder and an impression cylinder for printing a sheet on one side, a first drum positioned in cooperative engagement with said impression cylinder, grippers on said first drum adapted to release the sheet after completion of printing thereon by said plate cylinder, axially parallel drum transporting and drying-promoting devices mounted on said main frame in a successive cooperating series for transferring a printed sheet to said perfecting unit from said first drum, said first drum and said drum transporting devices being mounted in position to prevent contact with the freshly printed side of the sheet to be transferred, alternate drums of said series being fitted with a sheet metal jacket and means for delivering a perfected sheet to a stack, said main frame being provided with access opening means for bringing printing cylinders into and out of position for mounting in said machine.

References Cited in the file of this patent Pritchard Feb. 6, 1951 UNITED STATES PATENT OFFICE Certificate of (Zerrectien Patent No. 2,865,288 December 23, 1958 Georg Kalrlschmidt it is hereby certified that errer appears in the above numbered patent requiring correction and that the said. Letters Patent should read as corrected below.

In the grant, lines 2 end 12, and in the heading to the printed specification, line 5, name of asslgnee, f01'Veb Druchmaschmenwerk vlctorle, each occurrence, read Veb Druckmaschmenwerk V1ct0r1a-.

Signed and sealed this 28th day of April 1959.

[emu] Attest= T. B. MORROW, ROBERT C. WATSON,

Attestz'ng Ofiicer. C'ommz'ssioner a Pixie-mf 

